This is an application for funds to support clinical and basic research on several aspects of stroke and related problems in the cerebrovascular diseases. The Program Project consists of a Clinical Unit designed to provide superior consultation and teaching on problems of stroke at the New York Hospital-Cornell Medical Center. Clinical investigation in cerebral blood flow will be continued and studies on altered platelet function in cerebrovascular disease are planned. Basic studies will be directed at: determining the biochemical basis for cerebrovascular autoregulation; identifying whether anoxia or ischemia or both are responsible for cerebrovascular injury in the newborn; and trying to work out appropriate treatments for this condition; identifying whether the vascular endothelium or the brain tissue itself is selectively the most vulnerable to anoxia, and whether ischemia is always required for the production of tissue necrosis in the brain. Other investigators in the project will examine the physiologic mechanisms and potential treatment of central neurogenic hypertension. Another group will attempt to establish the exact pathogenesis of hypertensive cerebral hemorrhage. Neuroradiologic studies are planned at, respectively enlarging the scope and accuracy of angiotomography, working out the mechanisms of cerebral ventricular enlargement, determining the blood supply of pacchionian granulations and investigating tissue radiation absorption in an effort to develop better non-invasive radiographic contrast procedures for patients with stroke and allied diseases.